Exercise bike



FIG. 1 is a rear isometric view of an exercise bike of the present invention, with the broken lines representing an environment of the exercise bike and forming no part of the claimed design;

FIG. 2 is a right elevation view of the exercise bike of FIG. 1;

FIG. 3 is a front view of the exercise bike of FIG. 1;

FIG. 4 is a left elevation view of the exercise bike of FIG. 1;

FIG. 5 is a rear elevation view of the exercise bike of FIG. 1, with the broken lines defining the bounds of the exercise bike and forming no part of the claimed design;

FIG. 6 is a top view of the exercise bike of FIG. 1, with the broken lines defining the bounds of the exercise bike and forming no part of the claimed design; and,

FIG. 7 is a bottom view of the exercise bike of FIG. 1. 

The ornamental design for an exercise bike, as shown and described. 